1. Field of the Invention
This invention relates to devices, e.g. grommets, for gripping and sealing around elongate substrates, e.g. strip heaters.
2. Introduction to the Invention
Elongate substrates, e.g. electrical leads or strip heaters, must be sealed at each power connection, splice, tee, or end termination in order to provide electrical insulation and environmental protection. A conventional method of making such a seal is with an elastomeric grommet or sealing ring. Devices of this type are disclosed in U.S. Pat. Nos. 3,109,662 (Bergstrom), 3,163,882 (Falkenberg) and 4,383,692 (Proctor) and British Patent Nos. 1,037,048 (Cottrell) and 1,361,492 (Hamblin), the disclosures of which are incorporated by reference herein. Such conventional grommets must be sized for each individual application in order to provide adequate sealing, pullout force, and strain relief to the elongate conductor. As a result, for a length of conductor on which a number of connections, splices, or terminations are to be made, a large number of grommets must be available.
Some grommets, such as that disclosed in U.S. Pat. No. 4,614,390 (Baker), the disclosure of which is incorporated by reference herein, are designed with a peripheral groove so that under compression the two halves of the grommet on either side of the groove can collapse to form a stronger seal on the conductor. Because the center bore for this grommet is of uniform diameter, the grommet must still be sized for each application.